Degradation of quality of groundwater is a challenge faced by the water resource sector. Treated wastewater) TWW) is the water that is generated after removing contaminants from wastewater and household sewage, both runoff (effluents), domestic, commercial and institutional. Wastewater volumes in Oman are rising and continuously available due to growing urban populations. Every day at least 15 % of the production of TWW is dumped to the sea and this percentage is increasing. The objectives of the research are to estimate the farmers willingness to pay (WTP) for treated wastewater and to identify the factors that affect the farmer WTP for treated wastewater. The method used to estimate the farm owners WTP is the Contingent valuation method. Barka was chosen as the study area because of its close proximity to the new Seeb Sewage Treatment Plant. Only 72 surveys were collected for the study due to several difficulties such as absence of right person to answer the survey in the farm. The results indicated that a farmer WTP for TWW is significantly affected by the income and whether the farm is a commercial or hobby farm. Commercial farm owners will invest in their farm and cultivate if supply of water is ensured unlike the hobby farmers. The sign of other variables were as expected but they were not significant at 5% level. The average calculated WTP is 0.111 OR/m*. The percentage of farmers willing to pay this price or higher is only 38%. Sixty two percent of the farmers are willing to pay this price or less. Haya water is selling TWW at 0.220 OR/m' which most of farmers didn't accept paying as it is not a profitable price. , The mean WTP is 0.128 and 0.87 OR for the hobby and commercial farmers respectively. That is indicating that hobby farmers are more willing to pay for TWW than commercial farmers. It is clear that farm owners are in need of TWW to re-cultivate their farm, Haya water should find a way to provide these farms with this water in reasonable prices were they can benefit either as commercial or hobby farmers instead of dumping it to the sea.